simplified handling newly added columns

stand.py

@@ -24,10 +24,8 @@ changed = restapi.changed
 df = restapi.data
 
 
-columns = st.session_state.get("columns", set())
+# encode the column names into the key, thus trigger a hard reload (like F5) when the columns change
-new_columns = set(df.columns)
+key = "stand:" + "+".join(str(col) for col in df.columns)
-cols_changed = (columns != new_columns)
-st.session_state.columns = new_columns
 
 
 
@@ -79,7 +77,7 @@ response = AgGrid(
     fit_columns_on_grid_load=True,
 
     reload_data=changed,
-    key=None if cols_changed else "stand" # None triggers a hard reload like F5, which is needed if new columns were added
+    key=key
 )